Display panel or portion thereof with a graphical user interface



The sole FIGURE is a front view of a display panel or portion thereofwith a graphical user interface showing our design.

The outermost broken line illustrates a display panel or portion thereofthat forms no part of the claimed design. The remaining broken lines,including all text, illustrate portions of a graphical user interfaceand form no part of the claimed design.

CLAIM The ornamental design for a display panel or portion thereof witha graphical user interface, as shown and described.